Is There Another Name for Vitamin K2?

If you have ever spent time looking at the back of a supplement bottle or reading about heart and bone health, you may have noticed that vitamins often come with a variety of confusing labels. You might see one product listed simply as Vitamin K, while another specifies Vitamin K2, and a third uses a term like "MK-7." This can leave you wondering if you are looking at the same nutrient or something entirely different.

The short answer is that Vitamin K2 is most commonly known by its scientific name: menaquinone. However, the naming convention does not stop there. Because Vitamin K2 is actually a group of related compounds, you will often see it referred to by specific subtypes like MK-4 or MK-7. Understanding these names is more than just a lesson in chemistry; it is a critical part of knowing what your body is actually absorbing.

At Cymbiotika, we believe that wellness starts with transparency and education. We want you to feel empowered when choosing what goes into your body, which means understanding not just the names of vitamins, but how their specific forms impact your health. In this guide, we will break down the different names for Vitamin K2, why the subtypes matter, and how to choose a form that your body can actually use.

When scientists speak about Vitamin K2, they almost exclusively use the term menaquinone. This is the formal, chemical name for the entire family of K2 vitamins. While Vitamin K1 is known as phylloquinone, Vitamin K2 is categorized as a group of "menaquinones."

The name menaquinone refers to the chemical structure of the molecule. All Vitamin K compounds share a common "ring" structure, but they differ in the length of their side chains. In the case of Vitamin K2, these side chains are made of repeating units called isoprenols. This structural difference is why K2 behaves so differently in your body compared to K1.

Quick Answer: The most common scientific name for Vitamin K2 is menaquinone. It is also frequently referred to by its subtypes, most notably MK-4 (menatetrenone) and MK-7.

Understanding the "MK" Suffix

You will rarely see Vitamin K2 listed on a high-quality supplement label without an "MK" followed by a number. This abbreviation stands for Menaquinone, and the number that follows represents the number of isoprene units in the side chain of that specific molecule.

Think of the "MK" as the family name and the number as the individual's name. While they all belong to the same family, their "personality" and behavior in your body change based on that number. For example:

• MK-4 has four isoprene units.
• MK-7 has seven isoprene units.
• MK-9 has nine isoprene units.

The length of this chain is not just a technical detail. It directly dictates how bioavailable the nutrient is—which refers to how well your body can absorb and use it—and how long it stays active in your bloodstream. If you want a deeper look at why that matters, Cymbiotika’s guide on Why Bioavailability Matters: What All Is Magnesium Glycinate Good For? is a helpful place to start.